いたずらに会議体を作って、賛否両論を並べ、これ以上時間を費やすのは賢明とは思えません。(source)
しかし、何時までも状況改善を待つことは賢明とは思えません。(source)
今日のあなたの服装はとても仕事向きの服装とは思えませんが。(source)
I am under the impression after a 名詞/形容動詞, 「だとは思えません」 and the だ-less 「とは思えません」 both seem to occur. But I've always learned that と思う calls for だ if the it follows a 名詞/形容動詞. What's happening? Is it the particle は or the structure 思えない that's key to this change?
I’m not sure if this と should be grammatically categorized as quotative. If it is, the quoted part consists of only the adjective 賢明 in the first and second sentences, and only the noun phrase 仕事向きの服装 in the third, as what precedes them in each sentence (excluding the adverb とても in the third) is the topic of the main clause and not part of the quote.
For the sake of explanation, let me take out the main part of the second sentence as an example and mark the quoted part with brackets.
- 状況改善を待つことは［賢明］とは思えません。
This sentence (#1) sounds no less natural to me than the following version with だ (#2).
- 状況改善を待つことは［賢明だ］とは思えません。
Now, let us replace the topic marker は with が to put the topic into the quote as the subject.
- ［状況改善を待つことが賢明］とは思えません。
- ［状況改善を待つことが賢明だ］とは思えません。
If the と is indeed quotative, I would expect the latter (#4) to sound much more natural than the former (#3). However, this doesn’t seem to be the case as the version without だ (#3) still sounds natural enough to me.
In contrast, of the following pair, in which とは思えません is changed to と思います to make the と undoubtedly quotative, the former (#5) does sound significantly less natural than the latter (#6).
- ［状況改善を待つことが賢明］と思います。(?)
- ［状況改善を待つことが賢明だ］と思います。
This unnaturalness remains after the contrastive は is restored, too.
- ［状況改善を待つことが賢明］とは思います。(?)
- ［状況改善を待つことが賢明だ］とは思います。
This leads me to think that, despite the verb 思う, the と in Ａが／はＢとは思わない／思えない may better be understood along the same lines as that in such expressions as Ａが／はＢとは限らない than as a typical quotative と as in Ｘと思う.
